Catheters which are used to infuse fluids into a vascular system and which incorporate occluding wires are well known in the art. Typically, such a catheter has an elongated body with proximal and distal ends. A catheter lumen is formed interiorly of the body. A hole or opening is located at the distal end of the body so that fluid can pass from the catheter lumen through the hole into the vascular system. This opening also provides a passageway through which a guide wire can fit. Fluid material intended to be delivered to the vascular system is introduced into the catheter lumen through its proximal end. Pressure responsive exits in the form of slits may be arranged in a side wall of the catheter body as a means for infusing the fluid material from the catheter lumen into the vascular system at a desired rate and location. Occluding wires are typically arranged so that they extend longitudinally within the lumen and fit into the opening in the distal end blocking fluid from exiting the end hole. The opening therefore serves as another means for passage of fluid from the catheter lumen into the vascular system depending on the position of the occluding wire. When the occluding wire is in the occluded position, the distal end hole will be closed and fluid will pass through the slits. If the occluding wire is removed from the catheter lumen, then fluid will pass through the end hole. When infusing fluid into the vascular system through such a catheter, it is necessary to have a fitting or other structure connected to the catheter, at its proximal end, in order to provide a means for introducing the fluid material into the catheter lumen and to secure the occluding wire in place during infusion procedures. A common type of fitting or structure used for this purpose is a hemostasis y-adapter. An example of a hemostasis y-adapter as a means to secure an occluding wire is marketed by AngioDynamics, Incorporated, under the brand name of "Pulse*Spray.RTM.". The AngioDynamics.RTM. Pulse*Spray.RTM. Infusion System utilizes a hemostasis y-adapter with a Touhy Borst valve on the adapter's through lumen proximal end. The Touhy Borst valve provides a means to open and allow a guide wire to be inserted or withdrawn, or closed to provide a seal and retention mechanism around a guide wire. A rotating male luer fitting is attached to the distal end of the through lumen. This distal male luer fitting allows removable attachment to the catheter's proximal female luer fitting. A second side lumen intersects the through lumen of the adapter at an acute angle. The side lumen ends with a female luer fitting having a port to allow fluid to be injected into the y-adapter. The proximal end of the occluding wire passes through the through lumen of the y-adapter and extends through the Touhy Borst valve opening beyond its proximal end. The Touhy Borst valve incorporates a rotating cap which can be turned to open or close the valve around the occluding wire's proximal shaft. When such a catheter is in use, the occluding wire may be caused to move out of its desired occluding position, either as a result of some tortuous path experienced during catheter insertion, or it may be moved as a result of its engaging the inner walls of the catheter lumen during possible bending of the catheter. Therefore, the user may be required to manually adjust the position of the wire to insure its occluding function. Such an adjustment is a time-consuming and difficult maneuver to accomplish while trying to accurately place the catheter into a proper position within a patient to infuse fluid into the vascular system.
Y-adapters of the type discussed above are large and bulky. In prior known adapters, the fitting can have a length of several inches, thus they are difficult to handle in complicated catheter insertion procedures. In addition, such adapters are expensive and add cost to catheterization procedures. Another disadvantage of using y-adapters involves priming procedures. Prior to using any catheter, its lumen system must be primed in order to remove any air from the catheter as well as from any lumens or passages in an adapter to which the catheter is connected. Priming a catheter which has a y-adapter can be difficult in view of the fact that y-adapters involve multi-lumen configurations. Priming a y-adapter to be coupled to a catheter involves many steps and begins prior to connecting the adapter to the catheter. First, a normal heparinized saline must be slowly introduced through the side lumen by a syringe which is inserted into the side port. This continues until the saline drips out of its through port. The distal fitting of the y-adapter is attached to the catheter while more saline is pumped into the system, purging air from the Touhy Borst valve. The occluding wire can now be inserted through the Touhy Borst valve and into the catheter lumen. The occluding wire is advanced until the occluding ball seats into the catheter's tapered tip. While maintaining positive pressure on the syringe to prevent air from entering the adapter's lumen and pushing forward on the occluding wire to insure placement of the ball against the seat, the Touhy Borst valve is closed. Therapeutic fluid may now be introduced into the large volume occupied by the two lumens and passages of the y-adapter. This is a complicated and time-consuming process. In addition, this procedure requires large amounts of both saline and therapeutic fluids to complete the priming process, thus adding more cost to the catheterization procedure.
Because the occluding wire passes through the Touhy Borst valve and is thus exposed, there is the added risk that either a patient or medical personnel may inadvertently manipulate the proximal end of the wire which extends beyond the proximal end of the hemostasis y-adapter. Such inadvertent manipulation could result in ineffective occluding function of the wire, thus reducing effectiveness of the catheter during infusion procedures. Exposure of the wire beyond the y-adapter proximal end also increases possibilities of infection, as it is difficult to maintain a sterile condition of the wire.
Other difficulties with the prior art arrangements involve the need to be able to longitudinally adjust the position of the occluding wire during the catheter procedure due to the fact that the catheter may bend as it passes through tortuous pathways and the occluding wire may come into contact with the inner surfaces of the catheter side walls, thus resulting in variations in the length of engagement of the wire in the passageways. In order to compensate for this movement of the wire, it is frequently necessary to manually adjust the position of the wire in order to maintain full occluding of the hole at the catheter distal end. In order to achieve such manual adjustment, it may be necessary for the operator to conduct the adjustments by holding the y-adapter while simultaneously opening the Touhy Borst valve, adjusting the location of the wire, purging air from the y-adapter's lumen, and then retightening the valve, while maintaining sterility of all components. Improper adjustment could result in inefficient or failure of infusion of fluid into the vascular system, or could result in misalignment of the catheter in the vascular passages.